A common C2‐symmetric 2,2’‐biphenol building block and its application in the synthesis of (+)‐di‐epi‐gonytolide A

Abstract

A variety of biaryl polyketides exhibit remarkable bioactivities. However, their synthetic accessibility is often challenging. Herein, the enantioselective preparation and synthetic application of an axially chiral 2,2’‐biphenol building block is outlined that represents a common motif of these intriguing natural products. Based on the highly regioselective and scalable bromination of a phenol precursor, a coupling process by Lipshutz cuprate oxidation was developed. A copper‐mediated deracemization strategy proved to be superior to derivatization or kinetic resolution approaches. Key steps in the overall building block synthesis were rationalized through DFT studies. Utilizing the 2,2’‐biphenol, a highly diastereoselective five step synthesis of formerly unknown (+)‐di‐epi‐gonytolide A was developed, thus showcasing the building block's general potential for the synthesis of natural products and their derivatives. En route, the first enantioselective construction of a chromone dimer intermediate was established.